Basic MATLAB commands

My previous article was about defining scalar variables and evaluating arithmetical expressions in MATLAB.

Now, we're going to practice that and I will show you some basic commands.

Let's say we want to keep track of what we do in this session. For this, we have the diary command.

>> diary

This function will create a text file named diary that you can open later with any text editor.

If you want to give the file a name of your choise, use

>> diary FileName

(MATLAB automatically colours the file name in magenta).

More information about this command can be found by typing 

>> help diary

To see the current directory, where this file has been saved, use the the cd command.

You can change the current directory by specifing the path between apostrophes.

>>cd 'D:/'

Let's make the following four variables: a=2.5×10²³, b=2+3i (i being the imaginary number), c=e^j2π/3, d=√36.

>> a=2.5*10^23, b=2+3*i a =   2.5000e+023 b =   2.0000 + 3.0000i

In this case, the e notation is used for a very large number.

Notice that to enter multiple statements at once you can use commas.

For defining the c and d variable, we'll need some help from MATLAB and we'll have to search for the exponential function, for the pi constant and for a function that computes the square root of a number. 

>> lookfor exponential

Lookfor searches in the description of each function for a match, while help searches a function with the exact same name.

>> c=exp(j*2*pi/3); d=sqrt(36) d =   6

As you can see, semi-colons also allow placing several statements on one line, but, unlike commas, they will supress the output. 

For a list of the variables in the current workspace type:

>> who Your variable names are: a b c d

To see even more details about the variables, including size, class and attributes, use whos.

Remember that at the beginning of this session, you started a diary. Now, since the article is coming to an end, we should stop recording. For this, enter

>> diary off

 To view the diary file use

>> type('FileName')

 To remove all the variables from memory, MATLAB has the clear command.

>> clear

If you want to clear the Command Window, type

>> clc

My next article will be about working with vectors in MATLAB.